An inescapable fact or situation is one you cannot avoid or ignore. You may not like it, you may look away, but it is still there. People also talk about an inescapable conclusion: if you follow the facts, you land on it whether you want to or not. The picture is escape — running away — but the usual use is not about climbing out of a room. It is about truth, duty, results, and feelings you cannot dodge. It is a little formal, but you will hear it in news and careful talk, not only in books. Though actually, speakers sometimes call a thing inescapable when they only mean it is very likely, or when they want you to stop arguing.